is 2" piping too small from the IC to TB on a 95 accord f22b1 with a t3/t4? i am only going to run 6psi at first to make sure everything is working properly. a few weeks later i will probably upgrade to 2.5" piping along with tuning.
thanks

BTW i will be running 2.25" piping from the turbo to IC

edit: or should i just wait 2-3 weeks and get the 2.5" piping??

 

2" will work fine @ 6psi for a few weeks or more, in my opinion... maybe others may not agree but I think it is ok.

I would not worry about upgrading to 2.5" until you start upping the boost alot.

 

it should be more like 2in from the turbo to intercooler, then 2.5in or 2.25in to the intercooler to throttle body. hot side if need be....should be smaller then the cold side, never heard of it backwards, but if u just trying it out, then no biggie. but don't do it opposite tho, i would imangine you'd be making the turbo work harder and causing restriction.

 

The real question is what are the physics at hand here? I found a good excerpt by BryanPendleton: (http://forums.probetalk.com/archive/...p/t-20329.html)

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For the sake of being a complete discussion, If you are interested in pressure changes due to density changes in the fluid medium, simply refer to the conservation of mass law. The law states that mass cannot be created nor destroyed, so what goes in the intercooler must come out. If m1 goes in and m2 comes out, then m1 must equal m2. Now what is m1 and m2? Mass Flow Rate. What is the mass flow rate? Mass Flow Rate is the amount of mass that enters the intercoolers per some unit of time, or simply the Volumetric Flow Rate X Density. If the inlet and outlet dimensions are the same, and there is no density changes you can clearly see that the Volumetric Flow Rate will not change, but if you increase the outlet density, you clearly see that the Volumetric Flow Rate must decrease to conserve mass. Now what is Volumetric Flow Rate. Volumetric Flow Rate is the volume of the fluid that enters the intercooler per a unit of time, or Area X Velocity and since we said that the areas are the same the exit velocity must decrease. As for the pressure increase due to density change simply look at Bernoulli's equation. For a demonstration of Bernoulli's equation in action, simply take a strip of paper about an inch wide and several inches long. Hold on to one end of the paper. Place it up to your lips so you can blow air across the top of the paper strip. Without blowing air you will notice that the paper strip falls limp, but if you blow air across the top of the paper, it will actually rise. This happens because the still air on the bottom exherts more pressure on the paper strip than the flowing air across the top, so the paper strip rises. While you may have a increase in pressure, don't forget these gains neglibible compared to the viscous losses.

Other things to also consider is your intercooler volume. It may be tempting to stick an huge Mack truck intercooler on there because it offers a 0.10 psi pressure loose and is 99.9999% efficient (exaggerating) but the intercooler has such a huge internal volume that it takes your T3 compressor half a minute to pressure it up to the set boost levels. Here you can see the advantages of running smaller intake plumbing between the compressor and TB, while the pressure losses from running 2" pipe over 2.5" pipe may increase the pressure losses by 0.1 psi, but the system will reach boost 0.5 second earlier (Note that these numbers are just examples).
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The piping diameter depends on your intercooler design characteristics and turbo you plan to use. Its more of a tuning thing. If the intercooler flows to well, a smaller diameter pipe can "slow" the air flow and keep the hot air in the intercooler longer to get a cooler charge. But remember that an inter coler that flows too well needs a huge turbo that can fill it without working too hard.

My suggestion: 2.25 piping to the TB is fine. 2" is fine too. I would play with the sizes and monitor the output air charge temperatures to fine tune the setup.

 

Just thinking out loud:
Hot air takes up more volume than cold air. Compressing hot air in a 2 inch pipe will result in a specific pressure. When that air cools, (assuming the same volume), the pressure will decrease. When that air is placed into a 2.5 inch pipe, the pressure will decrease even more.

Seems like using bigger piping on the hot side would make the turbo work less because it would need to generate less pressure on the hot side to get the target pressure on the cold side. ?

Posted that ^ while I was typing.

 

well thanks for all the info and opinions..

i have my cai which is 2.75".. i am thinking of using that from the IC to the TB and using either 2" or 2.25" from the turbo to the IC.. this is my other immediate option. does this sound better in terms of my immediate options? sounds better to me just asking all you guys first, as I value your opinions..

thamks